The present invention is related to a pipe junction holder, and more particularly is directed to an improved pipe junction holder which can be used for connecting a pair of axially aligned liquid conduit pipes or tubes firmly together and for effectively preventing the pair of joined pipes from undesirable disengagement as occasionally occurs in the conventional prior art devices when an extraordinarily great pressure is abruptly applied in the axial direction.
Several types of pipe junction holders with disengagement preventing means are known in the prior art. The common type of the conventional pipe junction holder comprises a substantially annular body having a plurality of through holes with internal threads, each of the through holes being formed so as to radially extend so that its central line may meet at right angles to the longitudinal axis of the aligned pipes. A plurality of bolts are inserted into said through holes, each of the bolts having a threaded shank which is normal to a pipe periphery and passes through said hole in engagement with the internal threads of the hole. These prior art devices include a plurality of push members which are respectively interposed between the bottom end of the threaded shank and the peripheral surface of a pipe on which the pipe junction holder is mounted, each of said push members having at one side a rough, anti-sliding surface which is in contact with the peripheral surface of the pipe. In such a type of conventional prior art device, the pipe holding force, which is given by clamping the bolts, is constant, and as a matter of course, it is impossible to advantageously respond to a sudden increase in the pressure which is imparted in the axial direction to the internal surface of joined pipes by a rapid flow of liquid running through the pipes so as to let a pipe out of joint. Thus, it occasionally happens that one of the joined pipes is released from the other as an extraordinarily great pressure is experienced beyond the constant pipe holding force.
In addition to the above-described first conventional prior art device a further type of pipe junction holder as illustrated in FIG. 8 has recently been proposed. This second type of pipe junction holder comprises a substantially annular body 1 having a plurality of non-threaded through holes 2, each of the through holes 2 being elliptical in shape and extending radially so that its central line may meet at right angles to the longitudinal axis of aligned pipes 3. A plurality of bolts 4 are inserted into said through holes 2, each of the bolts 4 having a threaded shank 4a which is positioned perpendicular to a pipe periphery and passes through the hole 2 and a pair of edges 5 provided on the bottom end surface of each bolt shank. A plurality of nuts 6 are engageably mounted on each threaded bolt shank 4a, each of the nuts 6 having a slanted upper surface 7 which is declined away from a vertical wall 8 of the annular body 1. The slanted upper surface 7 is slidably contactable with an inclined surface 9 provided with one portion of the annular body 1. In this second type of prior art device, as the bolt 4 is turned, the bottom end of the threaded bolt shank 4a presses the peripheral surface of a pipe 3 on which the device is mounted, and at the same time, the nut 6 moves upward so that its upper slant surface 7 contacts the opposed slanted surface 9 of the annular body. Thus, when a great pressure is applied in one lateral direction so as to cause a pipe 3 to release and move slightly, the bolt 4 together with the nut 6 is also urged to move slightly in the same lateral direction within the elliptical hole 2. At this stage, as the slanted surface 7 of the nut 6 is urged to slide outwardly along the slanted surface 9 of the annular body, the former surface is forcibly pressed downward by the latter surface, resulting in that the bolt 4 is forcibly pushed down toward the pipe periphery so that a pair of edges 5 of the shank end can securely dent or eat into the pipe wall to prevent the pipe 3 from releasing. Thus, it will be easily understood that this second type of known prior art pipe junction holder is more advantageous as compared to the above-described first type of prior art devices in preventing the undesirable disengagement of joined pipes. However, the second type of prior art device still has a number of disadvantages. The first is that the contact area is not sufficient since it is limited to the bottom end surface of the bolt shank. The second is that the whole edges cannot eat into a pipe wall and also the edges cannot eat deeply into the pipe wall, because the bolt shank is disposed so as to be perpendicular to the pipe periphery. The third is that when a pair of edges are provided along the margin of the bottom end surface of the bolt shank in order to make the distance between the pair of edges as large as possible, they are easily broken, while, if the pair of edges are provided inwardly away from the margin of the shank end surface, the distance between the pair of edges is not enough to develop a satisfactory holding force to carry out the prevention of disengagement of the joined pipes. The fourth is that the structure is not very strong, durable or stable. Because of the four disadvantages mentioned above, the second type of known pipe junction holder has proved to be insufficient in developing a desired pipe holding force for preventing the disengagement of the joined pipes.
Accordingly, one of the objects of the present invention is to provide a pipe junction holder which eliminates all of the problems in the prior art as set forth hereinabove.
Another object of the present invention is to provide a pipe junction holder which develop a sufficient pipe holding force to prevent a pair of joined pipes from undesirable disengagement.
A further object of the present invention is to provide a pipe junction holder which includes a sufficiently large contact area with respect to a periphery of a pipe on which the pipe junction holder is mounted.
Still another object of the present invention is to provide a pipe junction holder which has a plurality of edges formed adjacent the bottom end surface of a bolt shank so that the edges can eat deeply into a peripheral wall of a pipe on which the pipe junction holder is mounted.
A still further object of the present invention is to provide a pipe junction holder which is very strong and durable in structure as well as stable in use.
Other objects, features and advantages of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description.
The pipe junction holder according to the present invention comprises a substantially annular body containing an annular projection which abuts against a known packing, at least three clamping blocks disposed in spaced relation with an equal interval therebetween, and a plurality of internally threaded through holes formed in the wall of the annular body. The holes extending in the wall of the annular body extend in parallel relation to the longitudinal axis of the aligned pipes on which the pipe junction holder is mounted. Each of said clamping blocks comprises a vertical front wall integral with said annular projection, a pair of side walls, and a lateral top wall which extends descendingly or downwardly away from said front wall. All of these walls are integral with one another, so that the clamping block is formed with an internal hollow space defined by said front wall, the top wall and a pair of side walls. The declined top wall presents an external and an internal surface, both of which are flat and smooth and extend in parallel with each other so as to become gradually declined as they get far from said front wall. Further, the top wall is provided with a non-threaded through hole which is elliptical in shape and extends perpendicularly relative to the inclined top wall. In other words, this through hole is inclined relative to the axial line of a pipe on which the pipe junction holder is mounted.
A bolt with an annular flange formed integral with its shank is received in said non-threaded hole with the flange slidably abutted on said internal slanted surface of the inclined top wall. The bolt shank is formed with threads at a portion between its bottom end and said annular flange. The bolt is arranged so that it can freely turn within the non-threaded elliptical hole and also can move in the direction of the longer diameter of the elliptical hole. At the threaded end portion of the bolt shank, a pipe pressing member is engageably mounted. The pipe pressing member is received within the hollow space of the clamping block in such a manner that its side walls are in contact with said side walls of the clamping block. Thus, the pipe pressing member is restricted from turning within the hollow space of the clamping block. The upper slanted surface of the member may come into contact relation with the lower surface of said annular flange of the bolt shank. On the bottom surface of the member there are provided a plurality of edges which are of such a configuration as to permit the denting or eating into a pipe peripheral wall.
In view of the construction as set forth hereinabove, when the bolt of the clamping block is turned, a pipe pressing member is moved downward to impart a clamping pressure to a periphery of a pipe on which the pipe junction holder is mounted, whereby an initial pipe holding force is obtained. Subsequently, when a great axial pressure produced by the liquid flow acts on the internal wall of the pipe so that the pipe is forced to move slightly outward, the bolt is also moved outwardly and at the same time the annular flange is urged to slide along the lower slanted surface of the top wall of the clamping block, resulting in that the bolt is forcibly pushed downward. Consequently, a pair of edges of the pipe pressing member securely dent or eat into the pipe wall to effectively prevent the further movement of the pipe. At this stage, because the bolt is inclined so as to counteract the movement of the pipe, the edges of the pipe pressing member can securely dent or eat more deeply into the pipe wall than those which are formed with the bolt shank end as disclosed in the prior art. Further, the distance between a pair of edges of the present invention can be set wider than that of a pair of edges provided with the bolt shank end as discussed in the prior art, and as a result, a more efficient and stable pipe pressing function can be achieved as compared to the prior art. Furthermore, the clamping block of the present invention is by far strong and more durable in structure as well as stable in use as compared to any of the prior art.